1. Field of the Invention
The present invention relates to a device for removing a broken piece of an instrument left in the root canal of a tooth, its supportive instruments, and a method for removing such a broken piece using them.
2. Description of the Related Art
The hard tissue of a tooth is corroded by lactic acid which bacteria produce by digesting food remains in the oral cavity and results in dental caries. In the dental treatment, when the lesion involves the dental pulp, root canal therapy is performed, in which the content of the pulp is removed, the root canal communicating with the pulp is enlarged as needed, the operated tissues is sterilized, and the resulting cavity is filled with an inert material such as gattapercha.
It is easily anticipated that instruments for treatment such as files etc. which are used for enlargement of the root canal in root canal therapy will be contaminated with debris, bacteria, etc. in removing dentin, cement and pulp etc.
It is ideal, therefore, to use disposable instruments for every new patient to be treated. In practice, however, the dentist usually repeats washing and sterilizing instruments every time after use, and keeps using until they turn out to no longer endure further use functionally.
In the later phase of its life after the repeated use for a long time, it occurs not infrequently that the tip of the instruments is broken off during treatment. Once the resulting piece is left in the root canal of a treated tooth, it is difficult to deal with the problem or remove the piece, and thus the piece often is left there.